The Journal of Medical Microbiology, Vol 34, Issue 5 253-257, Copyright © 1991 by Society for General Microbiology
The resolution of bacteroides lipopolysaccharides by polyacrylamide gel electrophoresis
J. P. Maskell
Department of Medical Microbiology, London Hospital Medical College.
The lipopolysaccharides (LPS) of the 10 species of the genus Bacteroides
(sensu stricto) were extracted by the proteinase K method and their
resolution compared by several methods of polyacrylamide gel
electrophoresis (PAGE). These included sodium dodecyl sulphate (SDS)-PAGE
with and without urea, polyacrylamide gradient gels and Tricine [N-Tris
(hydroxymethyl) methyl glycine]-SDS-PAGE. The original discontinuous system
showed good resolution of LPS from B. thetaiotaomicron, B. caccae and B.
ovatus and this was enhanced by urea; B. vulgatus showed a typical ladder
pattern associated with repeating polysaccharide units of the O side
chains. The LPS profiles of the other species, including B. fragilis, were
poorly resolved; the majority of components migrated with the leading edge
of the wave front. The resolution of the LPS of these species was
marginally improved with gradient gels but the majority of components were
separated only within the regions of high polyacrylamide concentration. The
Tricine-SDS system was consistently superior to the other methods, with
excellent resolution of the LPS profiles of all Bacteroides species.
